The invention relates to a filling device for motor vehicle air-conditioning systems, which is required for the maintenance of air-conditioning systems in order to exchange old spent refrigerant for new refrigerant.
EP 0 315 296 B1 discloses a refrigerant recovery system, by means of which refrigerant can be extracted from an air-conditioning system, purified and fed to the air-conditioning system again. This known refrigerant recovery system is suitable for air-conditioning systems which are operated with the refrigerants R12 or R134a. These refrigerants, because of their hydrocarbon content, are extremely harmful to the environment and should not be discharged into the environment, and it is therefore necessary to have a refrigerant recovery system of this type with a multiplicity of components, such as an evaporator, condenser, compressor and various valves, and with a complicated makeup.
A refrigerant recovery system of this type is not necessary or expedient for air-conditioning systems which contain harmless and natural refrigerants, for example, CO2.
One object of the present invention, therefore, is to provide a filling device for a motor vehicle air-conditioning system that uses harmless refrigerants, in particular CO2, which has a simple makeup and is correspondingly cost-effective and which meets a high safety standard.
Another object of the invention is to provide a method for draining and filling an air-conditioning system.
In accomplishing the objects of the invention, there has been provided according to one aspect of the invention, a filling device for a motor vehicle air-conditioning system comprising:
(a) a connection for connecting the device to the air-conditioning system;
(b) a drainage line, comprising a drainage valve, for draining off the refrigerant of the air-conditioning system at a predetermined rate;
(c) a pumping-off line which comprises a pump and is connected to the connection, for pumping off refrigerant residues substantially completely; and
(d) a refrigerant feed line, connected to the connection, for filling the air-conditioning system with refrigerant from a refrigerant source.
According to another aspect of the present invention, there is provided a draining and filling device for motor vehicle air-conditioning system comprising:
(a) a connector for connecting the filling device to a motor vehicle air conditioning system;
(b) a connecting line connected to said connector, said line comprising:
(i) a drainage line for draining off refrigerant from said motor vehicle air conditioning system;
(ii) a pumping-off line for pumping off refrigerant residues from said motor vehicle air conditioning system, and
(iii) a refrigerant feed line for filling said motor vehicle air conditioning system with refrigerant;
(c) a refrigerant outlet arranged at the end of said drainage line for discharging drained off refrigerant into the surroundings;
(d) a refrigerant reservoir connected to said line via said refrigerant feed line;
(e) a heater for heating said refrigerant reservoir and refrigerant contained therein; and
(f) a weighing device on which said refrigerant reservoir is mounted.
According to still another aspect of the present invention, there is provided a method of draining and filling a motor vehicle air-conditioning system comprising:
(a) connecting a connector of a filling device to a filling valve of said motor vehicle air conditioning system; closing a third shutoff valve; opening the filling valve as well as a first shutoff valve, a second shutoff valve and a fourth shutoff valve;
b) establishing refrigerant throughflow via said connector through a device for reducing pressure; discharging old refrigerant exiting from said device via an oil separator into the atmosphere;
c) pumping off substantially all refrigerant, moisture or dirt remaining in the motor vehicle air-conditioning system via said connector;
d) setting a filling pressure as a function of temperature and content of a refrigerant filling reservoir;
e) heating said refrigerant filling reservoir;
f) filling said motor vehicle air-conditioning system with refrigerant via said connector; and
g) separating said draining and filling device from said motor vehicle air-conditioning system.
Further objects, features and advantages of the invention will become apparent from the detailed description of preferred embodiments that follows, when considered together with the accompanying drawing.